[DERBY-7002] Change the text of X0Y84 to advise users to tune the value of derby.language.sequence.preallocator

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 10.15.1.3
• Component/s: SQL
• Urgency: Normal
• Assignee: Unassigned
• Reporter: Richard N. Hillegas
• Created: 04/Jul/18 22:01
• Updated: 06/Jul/18 23:02

Description

This is the LANG_TOO_MUCH_CONTENTION_ON_SEQUENCE error message. Right now it says the following:

Too much contention on sequence {0}. This is probably caused by an uncommitted
scan of the SYS.SYSSEQUENCES catalog. Do not query this catalog directly. 
Instead, use the SYSCS_UTIL.SYSCS_PEEK_AT_SEQUENCE function to view
the current value of a sequence generator.

Issue DERBY-6999 suggests that it would be good if the error message suggested another cause for the "too much contention" exception: The value of derby.language.sequence.preallocator may be too low. The error message should suggest that the user tune this value.

While we're at it, it might be good if the error message noted the current friction with Statement.getGeneratedKeys() (see DERBY-6934). Currently, there is no workaround for that friction. Application code should not call that method.

Issue Links

• relates to: DERBY-6934 Lock conflicts between Statement.getGeneratedKeys() and sequence-generator-based identity columns
• relates to: DERBY-6999 tooMuchContentionException thrown during concurrent inserts
• relates to: DERBY-5426 Improve the error raised by too much contention on a sequence/identity.
• relates to: DERBY-4568 Documentation needed for sequence generators